A properly worn arm sling keeps your elbow bent at roughly 90 degrees, with your hand slightly higher than your elbow and your palm facing your body. Getting this position right matters: too loose and the sling won’t stabilize your injury, too tight and you risk cutting off circulation to your fingers. Here’s how to put one on correctly and keep it comfortable for as long as you need it.
Getting the Position Right
The goal of any sling is to hold your forearm roughly parallel to the ground so your elbow sits at a 90-degree angle. Your wrist should tilt slightly upward (about 10 to 20 degrees) rather than drooping down, and your palm should face inward toward your stomach. This position reduces strain on your shoulder and keeps blood flowing properly through your arm.
Your hand should always sit a bit higher than your elbow. If your hand hangs below elbow level, fluid can pool in your fingers and cause swelling. A quick check: look at yourself in a mirror from the side. Your forearm should slope gently upward from elbow to wrist, not sag in the middle or tilt downward.
How to Put On an Envelope Sling
Most slings you’ll get from a hospital or pharmacy are the envelope type, a pouch of fabric with a single adjustable strap. Here’s how to fit one:
- Slide your elbow in first. Tuck your elbow all the way into the back corner of the pouch so the fabric cradles the entire forearm from elbow to wrist.
- Bring the strap behind your neck. The strap runs from the front of the sling, behind your neck on the opposite side, and connects back to the sling near your hand. Route it so it sits flat against the back of your neck, not twisted or bunched.
- Adjust the strap length. Tighten or loosen until your elbow rests at 90 degrees and your hand is slightly above elbow height. If the strap is too short, your shoulder will hike up toward your ear. If it’s too long, your arm will hang low and your shoulder will ache from the pull.
- Secure the swathe if you have one. Some injuries require a swathe, an elastic wrap that goes around the outside of the sling and around your torso, passing under your uninjured arm. This pins your arm against your body and prevents your shoulder from rotating. Your care team will tell you if you need one.
Broad-Arm Sling vs. High-Arm Sling
A broad-arm sling (sometimes called an elevation sling) supports your forearm with the hand just slightly above elbow level. This is the standard setup for most fractures, dislocations, and post-surgical recovery.
A high-arm sling holds the hand well above the elbow, often up near the opposite shoulder. It’s used when significant swelling needs to be controlled, such as after hand or wrist injuries, because elevation helps fluid drain away from the injury site. You’ll know which type you need based on what your provider sends you home with. If your hand or fingers are noticeably swollen, propping your arm higher generally helps.
Signs Your Sling Doesn’t Fit Right
Check your fingers several times a day, especially in the first 48 hours. Warning signs that the sling is too tight or positioned poorly include cold fingertips, numbness or a pins-and-needles sensation, white or bluish skin on your fingers, and visible swelling in the hand. If you notice any of these, loosen the strap, reposition your arm so your hand sits higher, and wiggle your fingers for a minute to encourage blood flow. If the symptoms don’t resolve quickly, that’s worth a call to your care provider.
On the neck side, watch for the strap digging into one spot. A thin strap concentrating all the weight of your arm on a narrow strip of skin will get painful fast. Folding a small towel or washcloth under the strap can help distribute the pressure. Some slings come with a foam pad for this purpose.
Sleeping in a Sling
You’ll likely need to wear your sling to bed for at least the first few weeks. Sleeping on your back is the most reliable option. Place a pillow under your injured arm so it stays supported even if you relax in your sleep. The pillow prevents your arm from rolling off your stomach and jolting you awake.
If you can’t sleep on your back, lying on your uninjured side works too. Hug a pillow with the injured arm so it stays elevated and cushioned, and tuck another pillow behind your back. That back pillow acts as a barrier to keep you from unconsciously rolling onto the injured side during the night. Sleeping on the injured side is not recommended, as your body weight compresses the injury and can increase pain and swelling significantly.
Skin Care Under the Sling
Fabric sitting against your skin all day traps heat and moisture, which can lead to irritation, rashes, and odor. Wearing a soft cotton T-shirt under the sling creates a barrier between the fabric and your skin, especially at the neck and inside the elbow crease where friction is worst. Change the shirt daily.
When you remove the sling briefly for hygiene (if your provider has okayed it), gently wash and dry the skin underneath. Pay attention to the crook of your elbow and the area behind your neck where the strap sits. If the sling itself starts to smell, most fabric slings can be hand-washed with mild soap and air-dried. Have someone help you keep your arm still in the correct position while the sling is off.
Exercises to Do While Wearing a Sling
Immobilization protects your injury, but it also causes stiffness remarkably fast. Gentle finger and hand exercises help maintain circulation and reduce swelling without disturbing the injured area. A simple routine: make a fist, then spread your fingers wide and stretch them back, and repeat. Aim for about 10 repetitions every hour you’re awake, building up to 30 if it feels comfortable. Five minutes of finger movement per hour is a reasonable target.
Pendulum exercises are commonly recommended for shoulder injuries once your provider clears you. Lean forward from the waist and let your injured arm hang straight down, slipping it gently out of the sling. Then let the arm swing like a pendulum: forward and back, side to side, and in small circles. Gravity does the work here, not your muscles. Start with 10 swings in each direction. These movements keep the shoulder joint from freezing up without putting force on healing tissue. Don’t start these on your own; confirm with your provider that your specific injury allows them.
How Long You’ll Wear It
Duration depends entirely on the injury. Simple soft-tissue injuries like sprains or mild strains may need a sling for only one to two weeks. Fractures typically require three to six weeks of immobilization. Post-surgical slings, particularly after rotator cuff repair, can be necessary for four to six weeks or longer. Your provider will give you a specific timeline. Removing the sling too early risks re-injury, but wearing it longer than necessary can lead to a stiff, weakened shoulder that takes months of physical therapy to restore. Follow the recommended schedule closely, and if you’re unsure whether it’s time to wean off the sling, ask rather than guessing.